Rapid Prototyping of Ultralow-Cost, Inkjet-Printed Carbon Microelectrodes for Flexible Bioelectronic Devices

Gaining better understanding of the human brain using chip-based devices and promoting the recovery of lost biological functionality through implants are long pursued endeavors driven by advances in material science, bioelectronics, and the advancing silicon technology. While conventional bioelectronic and neuroelectronic devices typically rely on cleanroom-based processing, a rapid prototyping technique is proposed that is based on high-resolution inkjet printing featuring nanoporous carbon electrodes that yield excellent cell–chip coupling. This study aims to overcome two major limitations of conventional approaches that make the development of neuroelectronic devices very challenging and limit a wider use within the research community as well as industry: high costs and lack of rapid prototyping capabilities. These challenges are addressed with an all-printed, high-resolution approach that makes use of flexible polymer substrates and is fabricated on a fully digital printing platform. The manufacturing of a chip consumes less than 60 min and costs a few cents per chip. This study introduces nanoporous carbon as a cell-interfacing electrode material that features outstanding properties for extracellular recording of action potentials and stimulation indicating that the printed carbon chips have the means to be used as a versatile neuroelectronic tool for in vitro and in vivo studies.